Upper Limb III

Question 1

Scapula (4)

Answer 1

Glenoid fossa laterally (which is the scapula’s contribution to the shoulder joint)

The spine on its posterior aspect, projecting laterally as the acromion process

The coracoid process on its anterior aspect.

Its strong muscular coverings protect the scapula and it is rarely frac- tured, only by direct and severe violence.

Page 168 diagram

Question 2

Clavicle general features

Answer 2

1) No medullary cavity
2) First bone to ossifiy in fetus (5th and 6th week)
3) Does not develop from cartilage
4) Most commonly fractured long bone

Question 3

Clavicle bony joints and relations

Answer 3

Split into 1/3
Medial 2/3 are convex anteriorly
Lateral 1/3 are convex posteriorly
Medial clavicle joined to 1st costal rib by costoclavicular ligament
Lateral clavicle articulates with the acromion process, joined to coracoid by the tough coracoclavicular ligament

Question 4

Clavicle vessels and nerves

Answer 4

Behind the medial third of the clavicle passes the subclavian artery (3rd part) and trunks of the brachial plexus separated by subclavius

Question 5

Important posterior relations

Answer 5

Posterior to the sternoclavicular joints lie the common carotid artery on the left and the bifurcation of the brachiocephalic artery on the right.

The internal jugular vein lies a little more laterally on either side. These vessels are separated from bone by the strap muscles—the sternohyoid and sternothyroid.

Question 6

Clavicle fracture

Answer 6

Trapezius is unable to support the weight of the arm so characteristic picture of patient with a fractured clavicle is that of a man supporting his sagging upper limb with his opposite hand.

The lateral fragment is not only depressed but also drawn medially by the shoulder adductors, principally the teres major, latissimus dorsi and pectoralis major.

Question 7

Humerus I

Answer 7

Head of the humerus consists of one-third of a sphere facing medially, upwards and backwards, separated from the greater and lesser tubercles by the anatomical neck.

The tubercles, in turn, are separated by the biciptal groove through which passes the long head of the biceps tendon

Question 8

Humerus II

Answer 8

Upper end of humerus and shaft separated by the surgical neck

The lower end of the humerus bears the rounded capitulum laterally, for articulation with the radial head

The spool-shaped trochlea medially, articulating with the trochlear notch of the ulna.

The medial and lateral epicondyles, on either side, are extra-capsular; the medial is the larger of the two, extends more distally and bears a groove on its posterior aspect for the ulnar nerve.

Question 9

Surgical neck of humerus

Answer 9

Axillary nerve

Circumflex humeral vessels

Question 10

Spiral groove

Answer 10

The posterior aspect of the shaft bears the faint spiral groove, demarcating the origins of the medial and lateral heads of the triceps between which wind the radial nerve and the profunda vessels

Question 11

Radius gross anatomy

Answer 11

Head
Neck
Shaft (the shaft has the radial tuberosity)
Expanded distal end (medial aspect of distal head articulates with ulna forming the infero radio-ulna joint)

Question 12

Ulna gross anatomy

Answer 12

• Olecranon fossa with trochlea notch
• Coronoid process with a radial notch for radial head articulation
• shaft with a small distal head (forms the inferior radio-ulna joint (medial articulation with the medial side of the radius)

Question 13

Ligament joining radius and ulna

Answer 13

Fibrous interosseous ligament

Question 14

Falling on outstretched hand produces differing injuries in a child, young adult and elderly

Answer 14

Young: Posterior displacement of radius epiphysis

Adult: radius and ulna shaft fracture

Elderly: Colles’ fracture

Question 15

Carpal bones

Answer 15

Proximal row: scaphoid, lunate, trquetral, pisiform (flexor carpi ulnaris inserts)

Distal: Trapezius, trapezoid, capitate, hamate

All carpal bones except lunate are broader posteriorly allowing an arched carpus with a concave palm

Question 16

Flexor retinaculum

Answer 16

From: Scaphoid and trapezium
to
Distal: Pisiform and hook of the hamate

Question 17

Carpal tunnel

Answer 17

The flexor retinaculum houses the flexors to the fingers and thumb and medial nerve.

Superficial palmar branch of the median nerve given off proximal to the flexor retinaculum palmar sensation is intact

Question 18

Shoulder joint stability

Answer 18

Rotator cuff muscles
long head of biceps
Long shoulder muscles

Deltoid
long head of triceps
pectoralis major
latissimus dorsi
teres major

Question 19

Rotator cuff muscles

SITS

Answer 19

supraspinatus (Insert into gtubercle)
infraspinatus (Insert into gtubercle)
teres minor (Insert into gtubercle)
subscapularis (Insert into ltubercle)

Question 20

Shoulder abduction

Answer 20

initiated by supraspinatus
Deltoid takes to 90 degrees
Trapezius and serratus anterior takes shoulder to 180 degrees

Question 21

Shoulder abductors

Answer 21

Supraspinatus

Deltoid

Question 22

Shoulder Flexors

Answer 22

Pec major
Corocobrachialis
Deltoid

Question 23

Shoulder Medial rotators

Answer 23

Pec major
Lat dorsi
Teres major
Deltoid
Subscapularis

Question 24

Shoulder adductors

Answer 24

Pec major

Lat dorsi

Question 25

Shoulder extensors

Answer 25

Teres major
Lat dorsi
Deltoid (Post fibres)

Question 26

Shoulder lateral rotators

Answer 26

Infraspinatus
Teres minor
Deltoid (Post fibres)

Question 27

Why is the shoulder prone to dislocation

Answer 27

The high mobility comes at the cost of stability. The inferior aspect of the humerus has no muscular protection therefore forceful abduction causes the humeral head to slip from glenoid fossa to lie in a subglenoid position and then anteriorly to lie in a subcoracoid position
N.B. Axillary nerve lies at the surgical neck along with anterior and posterior circumflex arteries

Question 28

Humeral shoulder dislocation

Answer 28

The humerus lies medially being drawn by the powerful adductors. The greater tubercle is no longer the lateral most bony projection but is replaced by the acromion process .

Question 29

Kocher’s method

Answer 29

Elbow flexed and forearm externally rotated to disengage subscapularis from internal rotation. The elbow is then swung medially across the trunk.

Question 30

Elbow joint

Answer 30

A synovial hinge joint made up of:
- Humero-ulnar: Humerus trochlea articulates with the trochlear notch of the ulna
-Humero-radial: Capitulum and the upper concave surface of the radial head (Ball and socket)
Superior radio-ulnar: Between head of the radius and radial notch of the ulna. The head is held in place by the tough annular ligament (pivot joint)
Elbow allows flexion and extension

Question 31

Elbow supinator

Answer 31

◊◊biceps
◊◊supinator
◊◊extensor pollicis longus 
◊◊extensor pollicis brevis 
◊◊abductor pollicis longus

Question 32

Biceps mode of action

Answer 32

Biceps attaches posteriorly to the tuberostiy of the radius

Biceps contracts causing the elbow flexion but then also radial supination

Question 33

Distal radius/ulna articulates with

Answer 33

scaphoid, lunate triquetral

Question 34

Brachial plexus gross anatomy

Answer 34

1) C5, C6, C7, C8, T1 are the original roots
2) C5/6, C7 and C8/T1form the Trunks
3) Six Anterior and posterior divisions are formed
4) Lateral, medial and posterior cord

Question 35

Axillary nerve course

Answer 35

Axillary nerve from C5/6 from the posterior cord plexuss winds around surgical neck of the humerus with the posterior circumflex arteries

Branches:
Muscular: deltoid and teres minor
Cutaneous: Palm sized sensation over the deltoid

Question 36

Axillary nerve disruption

Answer 36

Shoulder abduction weakness
wasting of the deltoid
muscle anaesthesia

Question 37

Radial nerve course

Answer 37

Main branch of the posterior cord (C5, 6, 7, 8 and T1)
Passes behind the axillary artery, between long heads of triceps and then lies in the spiral groove at back of humerus

Branch: Posterior interosseus nerve at the lateral epicondyle supplying extensor muscles of the forearm.

Radial nerve continues as the superficial radial nerve lying deep to brachioradialis, at the wrist emerges beneath brachioradialis to supply the radial 3.5 fingers.

Question 38

Musculocutaneous nerve

Answer 38

C5, 6, 7 supplies coracobrachialis, biceps and brachialis then becomes the lateral cutaneous nerve to supply the lateral skin of the forearm

Question 39

Ulnar nerve

Answer 39

C7, 8 T1 formed by the medial cord of the plexus
Passes the medial epicondyle to enter the forearm, in the distal 2/3 of forearm ulnar artery accompanies the nerve.

Branch: 5cm from the wrist the dorsal cutaneous branch supplies the dorsal ulnar side of the 1.5 fingers and ulnar dorsal side of the hand.

Ulnar nerve continues across the flexor retinaculum to supply the ulnar 1.5 fingers, a deep terminal branch supplies the hypothenar muscles and the intrinsic muscles.

Deep terminal branch:
Muscular: to the small muscles of the hand
cutaneous: Ulnar side of the hand and ulnar 1.5 fingers

Question 40

Median nerve course

Answer 40

Median nerve C6, 7, 8, T1) crosses the mid-humerus to lie medially. Nerve entersthe forarm between the heads of pronator teres

Branch: Anterior interosseous nerve supplies flex pollicis longus, flexor digitorum profundus and pronator quadratus

At the wrist the median nerve lies in the mid-line

Branch palmar cutaneous branch supplying skin of the midpalm.
Muscular branch to the flexors
Cutaneous: 3.5 fingers